// 商品类
class Product {
    private String title;
    private double weight;
    private String description;

    public Product(String title, double weight, String description) {
        this.title = title;
        this.weight = weight;
        this.description = description;
    }

    public double getPriceForQuantity(int quantity) {
        // 实际业务中需根据逻辑计算，此处仅为示例
        return 0.0;
    }

    public double getWeight() {
        return weight;
    }
    // 可根据需求添加其他方法
}
